1. Field of the Invention
This invention relates to an air bag in which cloths of a predetermined shape are laid on each other and are formed into a bag by joining their peripheries, and thereafter an inlet through which gas discharged interrelatedly with the actuation of an inflator enters the bag is formed in one of the cloths, and the bag is inflated with the gas which has entered through the inlet and is expanded diagonally to the rear of a vehicle from an opening formed in an upper part of an instrument panel.
2. Description of the Related Art
There is known an air bag device mounted in a vehicular instrument panel on the side of an assistant driver's seat (i.e., the seat next to the driver).
An example is also known in which an expansion opening through which an air bag is expanded is formed in an upper part of an instrument panel for structural reasons, such as the shape of the instrument panel, dispositional space requirements, or the like.
In the air bag device, a lid with which the expansion opening is closed is formed integrally with the instrument panel or is formed discretely therefrom. An inflator is mounted to face the back side of the lid in the instrument panel.
The inflator is provided with an air bag formed in such a way that cloths of a predetermined shape are laid on each other and their peripheries are joined. An inlet through which a pressure fluid enters is formed substantially in the center of one of the cloths.
The air bag begins to be inflated with the pressure fluid, such as gas, discharged interrelatedly with the actuation of the inflator.
The lid is cracked and opened by the expansion pressure of the air bag, and thereby the expansion opening is opened. The air bag continues to be inflated and expanded through the expansion opening obliquely toward the rear of the vehicle. Thus, the air bag cushions and protects the head, or the like, of the passenger at the assistant driver's seat so as not to be thrown forward directly into the instrument panel.
From the fact that the air bag is used to protect the head, etc. of the passenger in the event of collision, the time required until the air bag is satisfactorily inflated must be set to be extremely short.
A solution to this problem might be that the inflator is designed to discharge the fluid at higher pressure.
However, if the discharge pressure of the fluid becomes higher, the setting of the inflator will become very difficult because of the relationship with a sitting manner of the passenger.
In addition, if the expansion opening is directed upward, a front windshield is above the expansion opening.
Therefore, it is preferable to control the expanded direction of the air bag not to strike against the front windshield or not to strike against it at high pressure.